A common question raised is: when do I apply a heat transfer machine and when do I use an induction sealing machine?
Traditionally, you had no option but to heat seal when your product have no cap or closure that could tighten onto the body of the container. With the advent or development of capless induction sealing, the requirement for a cap is no longer there. This is why there is the questions, when do I use induction sealing and when do I use heat sealing?
Below are two Capless induction sealing videos:
Heat Sealing Explained
A physical constraint of heat sealing is the landing area where the sealing film will be applied and bond. Put simply, the landing area is the rim of the container and how wide that rim is. Where the rim of the container is less than 1/16th of an inch or about 1.6mm, induction sealing should be the preferred option. Heat sealing struggles with this thinner lip to seal onto.
You will notice on products like yogurt tabs, the sealing area has been turned up and may quiet wide often around a quarter of an inch or 45mm in width. This allows for a good area for the heat seal to apply.
And so we look the three areas: the cost of the material, the cost of the machinery, and the process – how easy it is to implement the machinery into your production.
Heat Sealing and Induction Sealing Material
The materials are broken up into foil line and just plastic film. Induction requires foil line, and therefore, is a more expensive material. Even comparing foil line for heat seal, induction is generally a bit higher because it has more thickness to it for the induction process to work properly.
A foil within the sealing material, be it induction or heat seal, will provide much better oxygen and waste barrier properties. Because of the natural, thicker material in induction sealing, it’s also a material more likely to peel off cleanly in one piece compared to a heat seal foil.
Heat Sealing and Induction Sealing Price Comparison
In terms of machinery, both heat sealing and capless induction sealing have some similar properties. In the semi-automated machinery side of things, they both quite low cost and you can get equipment for under $10,000 USD.
For more automated where you need speed to 30 products and beyond, machinery becomes more expensive. The machinery, in this case, requires cutting tools, to cut the material before placing it on the container’s sealing area. This represents a maintenance issue and also a cost issue. In both cases, equipment going for 30 products or more will cost at least $25,000 USD and often will go up to $80,000 USD.
Capless sealing could go beyond that and well into a $100,000 to $ 150,000 USD, when you are looking at 80 to 120 products per minute. Conventional induction sealing where the seal is placed into the cap prior to the cap being placed onto the product is much lower cost equipment. Each top induction equipment can start at around $1,500 USD. In line induction sealing usually ranges between $16,000 and $25,000 USD. Higher speed induction sealing where you might be looking at 150 products plus per minute can get up to about $40,000 to $45,000 USD.
Again, both in heat seal and capless induction sealing, you need to divide the products into a multiple lanes so that you can do the sealing at a reasonable rate of 30 plus to, say, a 120 products per minute. This adds to conveying costs and product movement costs and, indeed, the machinery costs. General advantage of induction sealing over heat seal are that the process can instantly, no time for waiting for the machinery to be ready. But with heat seal, you need to wait for the things to heat up and you need to watch the temperature has gone up to the right temperature before you proceeding into production. The safety side for the induction sealing is no direct heat so there is little chance for heat related injuries. No cutting tools to maintain for traditional induction sealing, while there are four capless induction sealing.
Material Ordering Volume
Regarding custom print on your material, lower volume are often easier to get with induction sealing material. By lower volumes, I am saying less than 500,000 pieces worth of material. For ease of use of equipment, for instant start up purposes, the sourcing of materials, I would put in order: convention sealing where the induction material with a seal placed into a cap prior to the induction sealing, then if that is not possible, capless induction sealing, and then finally, heat sealing.
Where the barrier properties are not that important, and cost is a consideration, it always is, you can save up to 1 to 2 cents if you go to heat seal. Just in the material side of things per product. The bigger the opening of the container, the bigger that saving will be. Typically heat seal for containers of 70mm or 3 inches approximately diameter can present significant material savings.
The SealerOn website shows both heat sealing and induction sealing with an emphasis on induction sealing.